The invention relates to a backrest for a vehicle seat with a backrest frame, which is surrounded by a cover and includes an upper backrest with an adjustable inclination.
The state of the art discloses backrests of this type in a variety of different embodiments. For example, DE 199 10 666 A1 discloses a vehicle seat, which has a seat section, a backrest and a headrest. The backrest is divided into two backrest sections, which can be pivoted about a horizontal axis in relation to each other. In this case, the upper backrest section bears a vertically adjustable headrest. The backrest, disclosed in DE 199 10 666 A1, is designed such that, during a rear end collision, the upper backrest section folds down in the forward direction against the lower backrest section. To this end, during a rear end collision the passenger, sitting on the vehicle seat, applies pressure to a mechanism in the lower region of the lower backrest section. The result of this action is that the upper backrest section along with the entire headrest, which is mounted thereon, is pivoted forwards. The drawback with this approach is that the cost of constructing such a design does not justify its use in the case of a seat with an integrated seat belt, where a seat belt D-ring is attached on the upper backrest section, because during a collision the passenger is pushed with enormous forces into the seat belt, and, hence these forces act on the pivot device between the upper and lower backrest section. In that case, the adjusting and locking devices between the upper and the lower backrest sections would have to be made very strong.
Another possibility that is disclosed in the state of the art for adjusting the inclination of the upper backrest section—thus, in the region of the shoulder blade—in relation to the lower backrest section is based on a totally different principle. In the case of such seats a single backrest frame is used that extends over both afore-mentioned regions of the backrest. Then the upper region of the backrest includes an inflatable body, which can be filled with air or can be deflated. In this way, the inclination of the upper backrest section is changed in relation to the lower backrest section as a function of how much air is present in the respective inflatable body. Since in this case a one-piece backrest frame is used, a seat belt D-ring can be fastened to this backrest frame, because there does not have to be a pivot axis, which is mechanically very stable, between the two sections of the frame. Therefore, such a construction can be used even in the case of a seat with an integrated seat belt. However, the drawback with this design is that it is very ineffective and slow. In addition, air conditioning functions in the vehicle seat can be realized only in partial areas thereof.
The object of the invention is to provide a backrest with an upper seat back with an adjustable inclination. This backrest withstands both high seat belt loads and can also be quickly adjusted. Moreover, it is not associated with a restriction on air conditioning functions.
This object is achieved with a backrest for a vehicle seat with a backrest frame, which is surrounded by a cover and includes an upper backrest having an adjustable inclination. An additional frame is hinged so as to be pivotable about a pivot axis on a side plate or to the cover or the backrest frame. The pivot axis is arranged in the upper region of the backrest, and the additional frame extends upwards from the pivot axis in the installed position of the backrest. The additional frame can be secured in different angular positions in relation to the backrest frame, and, thus, a variable gap forms between the additional cover of the additional frame and the cover of the backrest frame. Advantageous designs of the invention are described herein.
Owing to the fact that an additional frame is mounted on the otherwise continuous and one-piece backrest, in particular, a one-piece backrest frame, it is possible to also mount a seat belt D-ring on the backrest frame, which absorbs high seat belt forces. The pivotable hinge attachment of the additional frame on a side plate, the cover or the backrest frame can be carried out very easily, because it does not have to absorb any seat belt forces whatsoever. Owing to the fact that the additional frame can be secured in different angular positions relative to the backrest frame, good flexibility is guaranteed when a unique adjustment is made with respect to the current passenger. As a result, a variable gap forms between the additional cover of the additional frame and the cover of the backrest frame. In an extreme position, this gap can be reduced down to zero.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.